CD Markers

Author: Nat Pernick, M.D. (see Authors page)

Revised: 8 January 2016, last major update August 2013

Copyright: (c) 2003-2016,, Inc.

PubMed Search: ICOS
Cite this page: CD278. website. Accessed October 19th, 2018.
Definition / general
  • Also called ICOS
  • Enhances basic T-cell responses to a foreign antigen, namely proliferation, secretion of lymphokines, upregulation of molecules that mediate cell-cell interaction and effective help for antibody secretion by B-cells
  • Essential both for efficient interaction between T and B-cells and for normal antibody responses to T-cell dependent antigens
  • Plays a critical role in CD40-mediated class switching of immunoglobin isotypes
  • A type I membrane protein
  • Defects cause ICOS deficiency (OMIM 607594), a form of common variable immunodeficiency characterized by recurrent bacterial infections of the respiratory and digestive tracts, but without splenomegaly, autoimmune disease, sarcoid-like granulomas, overt T cell immunodeficiency
  • Present in: activated T cells, tonsillar T cells, fetal and newborn thymic medulla
Additional references